H. Elabd and W. F. Kosonocky in their U.S. Pat. No. 4,663,656 issued May 5, 1987, entitled "HIGH-RESOLUTION CCD IMAGERS USING AREA-ARRAY CCD'S FOR SENSING SPECTRAL COMPONENTS OF AN OPTICAL LINE IMAGE", assigned to RCA Corporation, and incorporated herein by reference describe an area-imager architecture suitable for connection in array as an extended width imager. FIG. 2 of the drawing of the Elabd et alii patent shows two side-by-side A.sub.1 and A.sub.2 image registers having respective rows for sensing red, green, blue and infrared spectral components of a line image. The side by side A.sub.1 and A.sub.2 image registers together extend across the entire width of the monolithic semiconductor die on which the extended-width imager is constructed. The A.sub.1 and A.sub.2 image registers periodically transfer charge packets to respective B.sub.1 and B.sub.2 field storage registers disposed on opposite sides of their respective image registers. This allows parallel-to-serial-converting C.sub.1 and C.sub.2 line registers, at the opposite ends of these B.sub.1 and B.sub.2 filed storage registers from their respective A.sub.1 and A.sub.2 image registers, to clock out streams of charge packets to respective E.sub.1 and E.sub.2 electrometer stages that are located at the ends of the C.sub.1 and C.sub.2 line registers opposite the die edges.
It is desirable to be able to increase the sensitivity of an extended-width CCD area imager by using a time-delay-integration (TDI) mode of operation. This cannot be done with conventional TDI imagers because only one direction of TDI operation is available.
H. Elabd in his U.S. patent application Ser. No. 938,863 filed Dec. 8, 1986, entitled "STORAGE REGISTERS WITH CHARGE PACKET ACCUMULATION CAPABILITY, AS FOR SOLID STATE IMAGERS", assigned to RCA Corporation, and incorporated herein by reference describes ways to achieve TDI operation for either of two opposing directions of motion using substantially the same imager structure. (This application, which is allowed and has had its issue fee paid, is a continuation-in-part of U.S. patent application Ser. No. 797,236 filed Nov. 12, 1985). These ways of achieving TDI operation involve field storage registers being of a special construction allowing the shuffling of the order of lines of charge packets in the rows of the registers.